Polylactic acid (PLA) is a highly biodegradable polymer that may be derived from natural sources, such as corn. The use of PLA for making food packaging trays is increasingly popular, due at least in part to its easy biodegradability and the fact that trays made from it have very high oxygen and moisture permeation rates and are therefore well suited for packaging fresh produce. However, trays made from PLA tend to soften and deform at temperature as low as 104° F. (40° C.). Because of this drawback, a critical requirement for lidding films for use on PLA trays is that the heatseal must be formed at a low temperature (around 200° F., or 93° C.) with a short dwell time (less than 2 seconds). Conventional sealant films either do not heat seal to PLA trays at low enough temperatures, or the heatseal strength deteriorates over time after the seal is made. Coextruded PLA films having one amorphous PLA layer and one crystalline PLA layer are capable of being sealed to PLA trays at low temperature, but such films are typically very brittle and tear easily, and do not run well on packaging lines, especially at high speeds. As indicated by the above, it would be beneficial to provide a lidding film that meets both the sealing performance requirements for use on PLA trays and the film processability performance required for practical commercial use.